Friction draft gear



June 29 1926. 7 1,590,712

" E. H. WALKER "FRICTION DRAFT GEAR Filed August '7. 1924 2 Sheets-Sheet 1 .EUU

June 29 1926.

E. H. WALKER 1 111011011 DRAFT GEAR Filed August 7. 1924 2 Shuts-Sheet 2 Patented June 29, 1926.

UNETE STATES OFFICE.

EDMUND I-I. WALKER, OF NEW YORK, N. Y.

FRICTION DRAFT GEAR.

Application filed August 7, 1924. Serial No. 730,667.

the course of time, result in lost motion so that when an impact is applied, as when coupling cars, a hammer-like blow results which, not being properly cushioned, will cause crystallization of the metal and consequent breakage.

It is with the above facts in view that I have designed the present invention which has for a more'particular object the provision of a draft gear of the friction type including a central and outer wedge blocks and embodying wear plates which are 1mtially placed in position and which may sub sequently be removed to permlt the central wedge member engaged by the sprlngs to move forwardly and take up any looseness between the areas of contact of the central wedge member with the outer wedge members and between the outer wedge members and the friction box.

A further object of the inventlon 18 to provide a friction draft gear not only embodying the above mentioned feature but further provided with means for reducing the length of the spring space within the barrel by a distance corresponding to the extent of forward movement of the central wedge member upon removal of the wear plates so that the length of the springs will-be the same after removal of the wear plates as before.

To the attainment of the foregoing and other objects and advantages, the invention consists in the details of construction and arrangement to be hereinafter moiefully described and claimed and illustrated in the accompanying drawings, it being, however, understood that the embodiment disclosed is merely a "preferred exemplification, as many changes and modifications may be made provided that constitute no departure from the spirit of the invention or the scope of the claimshereunto appended.

In the drawings wherein like reference characters designate corresponding parts throughout the several viewsz- Figure 1 is plan view illustrating the friction draft gear positioned in arailwav draft rigging. u

Figure 2 is a central vertical longitudinal section through the friction draft gear with the central wedge member in section and the outer wedge members in elevation.

. Figure 3 is an end view from the left side of the draft gear shown in Figure 2.

Figure 4- is a view partly in longitudinal section at right angles to the plane in which F igure 2 is taken, the view being indicated by the line 4-4 on Figure 2.

Figure 5 is a view partly in longitudinal section similar to Figure 2 and showing the position of the parts subsequent to removal of the wear plates, this vlew also illustrating the take-up plate provided at the rear of the barrel.

Figure 6 is a cross section on the line 66 of Figure 5,1ooking toward the take-up plate or filler. p

Referring to the drawings in detail, I have shown, in Figure 1, the invention applied to a friction draft gear positioned within a railway draft rigging involving the horizontal two-key Farlow construction in which the center sills 1 are provided with cheek plates 2 which, together with the sills, are suitably slotted for the accommodation of the keys in the usual manner. Located between the sills is a horizontal yoke 3 which has the forward ends of its arms slotted to receive the key 4 which connects the coupler 5 with the yoke, this key also extending through certain of the alined slots in the sills and cheek plates. Another key 6 extends through a second series of slots in the A sills and cheek plates and also through slots provided in the yoke arms and in a follower block 7 interposed between the butt of the coupler and the friction device. The numeral 8 designates a rear stop member or back stop located between the sills and with which the rear of the yoke contacts.

The draft gear or cushioning mechanism comprises a spring barrel or casing 9 which is engaged at its forward end within a friction box or head 10. This box is here represented as of rectangular form and is provided with inclined friction faces 11 with which cooperate the correspondingly inclined faces of outer friction members or wedge blocks 12 between which is arranged a central friction member or wedge block 13 which is movable through or within a central opening 14 in the head or box 10, The

larger, inner or rear, end of this central wedge member is formed with a flat face'or seat 15 at the center of which is a rearward projection 16 extending through an opening 17 in a spring plate or follower 18 ot a size to be capable o1 free movement longitudinally within the barrel and partly into the head or box 1O. lVithin the barrel are outer and inner springs 19 and 20, respectively, which bear against the closed outer or rear end wall 21 of the barrel and which bear also against the spring plate 18.

The outer or inclined surfaces of the central wedge inei- 'iber C18 are :lorined with grooves 22 which receive ribs 23 on the contacting faces of the outer wedge members 12, he corners of the outer wedge members adjacent the center wedge member preferably cut away, as indi ate'd atQ, for the purpose of preventing incorrect assembling as it is obvious thatthe sn l outer surfaces of the outer wedge bloc tended to engage th smooth inc red surfaces 11 of the friction box. The provision of the into-flitting ribs and "grooves oi ital importance inasmuch as they will insure proper movement of the parts whn subjected to strain or impact, and dan er of tipping or canting the wedge blocks will be prevented, while at the same time the proper frictional resistance is insured.- O viously, vhen pressure comesagainst the wedge blocl-;s, the outer ones 12 will move toward each other and toward the closed end of the barrel while the centralone will move longitudinally into the barrel the resistance ofthe springs 19 and 20. An excessive shock causes all the wedge blocksto move to such an extent that the follower 7 will engage the friction box 10 itself and V transmit the strain through the barrel 9 to the rearstop 8. p

n In a structure of this character it is quite apparent that after prolonged use the frid tion at the contacting faces will cause wear which must be taken up to avoid lost motion, hammering and consequent crystallization. Inview of this necessf 'torzn-the central wedge block 13 with lateral etensions or lugs 25 extending within rec 3 26 in the b x r head 1 d ithi th ece a e located the shims or wear plates 2-? against which the extensions-or lugs 25 abut. When in the course of time the parts have worn to such an extent that an undersired loosenessexists, it is intended that these shims or plates be removed or replaced with thin ier plat so hat th ce t al W d m er will be adapted to move forwardly a suffi entyjdis a se .t mp ns te fo the w ar i i-Pea the new pane-11g su face 101 forward. Yemen? at {th wedg 13 u e cor spo d ng mo m nt at h edges l2 resets, th re to efise veyoper ins position The removal or replacement of the shims or wear plates increases the distance within the barrel occupied by the springs and as this would be undesirable I make use of a filler ortake-up plate 28 which is disposed within the closed end 21 of the barrel and which may be held by a bolt 29 which passes through a counter-sunk hole 30 in the closed wall 21, through a suitable hole in the plate 28, and which is equipped with a nut 31. The thickness of the filler plate 28 is such as to compensate for the shims removed and may also take up the lost motion due to the set of the springs In the use oi a draft gear constructed in accordance \viththis invention, it is possible, by virtue of the removal or replacement of the shims or plates, to, prolong the lite ot' the mechanism to a great extent'inasmuch as the lost motion, with the resultant destruction 01 the parts, Will be eliminated,

Having now described my invention, what I claim is :c-

1.111 a friction-theft gear, a friction box having inclined surfaces, a barrel engaged with the box, outer. wedge blocks engaged within the box and having inclined stir-- faces contacting with the inclined surfaces thereof, a central wedge block located between and in engagement with the outer wedge blocks, a spring plate within the barrel engaging the central wedge block, springs within the barrel engaging said spring plate, and removable means positio nedbetween cooperating portions of the friction box and central Wedge block and normally limiting outward movement of the central wedge block with respect to the friction box. I p

In a r i dre tse r, a fri n b x hav ng' n urf a bar-rs engaged w t he x, oute e ge b ocks ngage withinxthe box and having inclined surfaces contacting with the inclined surfaces thereof, a central wedge .blO k, heated between and in engagement with "the outer wedge blocks, a spi'ingplatewithin the barrel en.- gaging the central wedge block, springs thin t a e ei g gi'l g'said spr ng plat and removable inea'iisnormally limiting outward movement of the 'cen' ra'l wedge block with respect to the "friction on, said means including shims located within the friction box, and extensions, on the central wedge blbek e g g n sa d shims-r j vl fi i Q l d af g a 'fl' rmt D b0? having inclined surfaces, a barrel engaged it e ot, out r We s: blee Biase w hin he box and is f c on ac ing wi h th thereof, a central w'd' twee and. sag s ed bloke, e snnnspl .e r 's' n the qe e. spr n s ithin th barrel f' s Q. spring plate, 'andremovable, normally limiting outward movement of the central wedge block with respect to the friction box, said means including laterally extending lugs on the central wedge block, and shims abuttingly engaged by said lugs, the friction box being recessed for the accommodation of said shims, said lugs and said spring plate.

4L. In a friction draft gear, a friction box having inclined surfaces, a barrel engaged with the box, outer wedge blocks engaged within the box and having inclined surfaces contacting with the inclined surfaces thereof a central wedge block located between and in engagement with the outer wedge blocks, a spring plate within the barrel engaging the central wedge block, springs within the barrel engaging said spring plate, and removable means normally limiting outward movement of the central wedge block with respect to the friction box, and means insertable within the barrel in abutting engagement with the springs therein to com pensate for the increase in distance between the spring plate and the opposite end of the barrel caused by removal of said first named means.

5. In a friction draft gear, a friction box having inclined surfaces, outer wedge blocks having inclined surfaces engaging said first named inclined surfaces, a central wedge block interposed between said first named wedge blocks and formed with lateral extensions, said friction box having recesses accommodating said extensions, shims re movably mounted within said recesses and abuttingly engaged by said extensions, a spring plate engaged against said central wedge block, and a spring within the barrel engaging said spring plate.

6. In a friction draft gear, a friction box having inclined surfaces, outer wedge blocks having inclined surfaces engaging said first named inclined surfaces, a central wedge block interposed between said first named wedge blocks and formed with lateral extensions, said friction box having recesses accommodating said extensions, shims removably mounted within said recesses and abuttingly engaged by said extensions, a spring plate engaged against said central wedge block, a spring within the barrel engaging said spring plate, and a filler plate adapted for lnsert on within the barrel in engagement with'one end of the spring to reduce the length of the spring space corresponding to the thickness of the shims.

In testimony whereof I aflix my signature.

EDMUND H. WALKER. 

